Update, move isHangul function

isHangul.js → hangul/isHangul.js

@@ -1,8 +1,15 @@
-const unicodeBlocks = require("./hangul/unicode/blocks");
+const unicodeBlocks = require("./unicode/blocks");
 const hangulBlocks = Object.entries(unicodeBlocks).filter(([blockName]) =>
   blockName.startsWith("HANGUL")
 );
 
+/**
+ * Check whether a provided character belongs to a Hangul Unicode block
+ *
+ * Returns null if input is not a string.
+ *
+ * @param {*} char
+ */
 const isHangul = char => {
   if (typeof char !== "string") {
     return null;

hangul/isHangul.test.js

@@ -0,0 +1,90 @@
+const isHangul = require("./isHangul");
+const {
+  BASIC_LATIN,
+  CJK_UNIFIED_IDEOGRAPHS,
+  CJK_SYMBOLS_AND_PUNCTUATION,
+  HANGUL_SYLLABLES,
+  HANGUL_JAMO,
+  HANGUL_COMPATIBILITY_JAMO,
+  HANGUL_JAMO_EXTENDED_A,
+  HANGUL_JAMO_EXTENDED_B
+} = require("./unicode/blocks");
+
+const describeTestBlock = (description, jamoBlock, expected) =>
+  describe(description, () => {
+    const [start, stop] = jamoBlock;
+    for (let charCode = start; charCode <= stop; charCode += 1) {
+      const char = String.fromCodePoint(charCode);
+      test(`should determine ${char} is not hangul`, () => {
+        if (expected) {
+          expect(isHangul(char)).toBeTruthy();
+        } else {
+          expect(isHangul(char)).toBe(false);
+        }
+      });
+    }
+  });
+
+describe("isHangul", () => {
+  describe("should return null", () => {
+    test("for an undefined input", () => {
+      expect(isHangul()).toBeNull();
+    });
+
+    test("for a null input", () => {
+      expect(isHangul(null)).toBeNull();
+    });
+
+    test("for NaN input", () => {
+      expect(isHangul(NaN)).toBeNull();
+    });
+
+    test("for an object input", () => {
+      expect(isHangul({})).toBeNull();
+    });
+
+    test("for a number input", () => {
+      expect(isHangul(1945)).toBeNull();
+    });
+  });
+
+  test("should return truthy for ㄱ", () => {
+    expect(isHangul("ㄱ")).toBeTruthy();
+  });
+
+  test("should return truthy for ㅏ", () => {
+    expect(isHangul("ㅏ")).toBeTruthy();
+  });
+
+  test("should return truthy for 가", () => {
+    expect(isHangul("가")).toBeTruthy();
+  });
+
+  describeTestBlock("basic Latin", BASIC_LATIN, false);
+
+  describeTestBlock(
+    "Chinese/Japanese/Korean unified ideographs",
+    CJK_UNIFIED_IDEOGRAPHS,
+    false
+  );
+
+  describeTestBlock(
+    "Chinese/Japanese/Korean symbols and punctuation",
+    CJK_SYMBOLS_AND_PUNCTUATION,
+    false
+  );
+
+  describeTestBlock("Hangul syllables", HANGUL_SYLLABLES, true);
+
+  describeTestBlock("Hangul jamo", HANGUL_JAMO, true);
+
+  describeTestBlock(
+    "Hangul compatibility jamo",
+    HANGUL_COMPATIBILITY_JAMO,
+    true
+  );
+
+  describeTestBlock("Hangul jamo extended-A", HANGUL_JAMO_EXTENDED_A, true);
+
+  describeTestBlock("Hangul jamo extended-B", HANGUL_JAMO_EXTENDED_B, true);
+});